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Re: Electric fan ideas

alabbasi is right. There's almost no electric fan that will move as much air as the mechanical fan. The bigger problem is lack of space for a large electric puller fan; IIRC there is only ~4 inches of space between the pulley and radiator on the W124+M119... don't know how much more room is on the R129. A big electric fan will pull around 40-50 amps so upgrading to a 150A alternator is a must. I don't know for sure but I doubt a big electric fan will be any lighter than the stock fan+clutch; if anything I suspect a big electric would be heavier! If the stock cooling system can't keep up with high temperatures, most likely something is wrong. When all the parts are working correctly, these cars/engines do not run hot unless it's unusually extreme circumstances.

Search the forum, the electric fan upgrade has been discussed in detail, Jelmer did the upgrade on his 500E years ago.

Also, you don't mention where you are located, but in a different post you mention km's so I'm assuming you are not located in USA...

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Re: Electric fan ideas for R129 SL500

In the 4 x 4 world the late 80's Ford Taurus and the Mark II fans are the bizzle. I installed one on my 1974 Bronco and it never ran cooler. It took a few relays and beefier wiring but worked fantastic. For fourwheeling they are great because you have full speed fan at low engine speed.

Re: Electric fan ideas for R129 SL500

Also, bear in mind any modern fan most likely is functioning off a PWM signal, not just a high/low speed relay... You can set up a pulse width modulator and take manual control of the fan Readily enough, but they don't typically just plug into 12v's anymore.

I'd also be a little suspect of gaining 20-30 hp from a cat delete. Only if your cats were Badly clogged could I see that being the case. Now if your cats Were clogged that would also explain the high temperatures you are reporting.

We've done electric fan conversions with custom radiators, but be forewarned..it's an expensive endeavour w/ a very Limited ROI.

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Re: Electric fan ideas for R129 SL500

Thank you very much for all the replies I don't know if I have enough space I will have to measured I figured how to work the pwm circuits so I know it can be done but not sure of the space constraints and the wiring.

Most at of the hp gain came from the exhaust delete the cat itself was no more than 5-6 bhp.

I have shaved off about 100 kgs off the car, I am located in Singapore.

stereo delete was about 7 kgs.

2 kgs off the head unit, 2 kgs off the cd changer 3-4 kgs by removing all the speakers and brackets.
spare tire and tools delete probably another 21 kgs.
hood insulation removed about 1 kg including the
the carpets and most of the covers have been removed
no rear bins removed and the hard top as well.

Re: Electric fan ideas for R129 SL500

Originally Posted by jhodg5ck

Also, bear in mind any modern fan most likely is functioning off a PWM signal, not just a high/low speed relay... You can set up a pulse width modulator and take manual control of the fan Readily enough, but they don't typically just plug into 12v's anymore.

I'd also be a little suspect of gaining 20-30 hp from a cat delete. Only if your cats were Badly clogged could I see that being the case. Now if your cats Were clogged that would also explain the high temperatures you are reporting.

We've done electric fan conversions with custom radiators, but be forewarned..it's an expensive endeavour w/ a very Limited ROI.

jono

Hi John,

Any custom oil coolers I noticed they are a bit small

i have a Ferrari 550 the oil cooler is 1/3 the size of the radiator and is covered by slightly less half an electric fan

if you do have custom radiators and fans do let me know

I would love to delete the two small front fans in favour of one big electric fan.

Re: Electric fan ideas for R129 SL500

I have converted my 500E to electric fans. A custom lightweight shroud was made & 2x 12 inch fans fitted. Along with a adjustable controller & temperature probe for the rad. A 150Amp Alternator & new Nissens Rad are also fitted.

I would like to point out that space is limited for the fans themselves so it is hard to get a powerful enough fan to fit in there. My car works great – but I live in Ireland. It’s always cold here! Moving along the fans never come on at all – only in traffic do they cut in & out.

Although no figures are available the CFM that the viscous fans can move is pretty immense – this could never fully by matched by electric fans. I too wanted the mechanical drag of the fan removed – but in the future I will make another cowl with a MB OE modern electric fan – requiring PMW signal. Figuring out how to integrate that to the 500E so as the fan constantly moves faster as temps increase will be key.

But be prepared to spend £££ figuring all of this out – and I myself am not fully convinced yet on if it’s worth it. I have a new Viscous coupling squirreled away just in case

Re: Electric fan ideas for R129 SL500

i can work out the pwm signal but I reckon we need 3500 CFM to beat the original mechanical fan.

i think the mechanical fan is close to 3000 at the peak maybe 3500

the two front pusher fans will probably contribute less than 1000 cfm

what know from a Ferrari 550 with dual fans

In a few places some list the SPAL VA18-AP70/LL/F-59A (AKA 30102113 - seems SPAL has two different part numbers for their fans) as the replacement 550 fan. That fan per SPAL puts out 3000 CFM and takes approx. 26 amps. It is unsealed and SPAL recommends this fan for racing applications only. I asked if there was potential for the fan to overheat a slow speed/idle and they said it was a possibility (eg they don't know). SPAL does not recommend these fans for use in passenger cars, however, they do say this fan is the closest they have to what is currently in our cars.

Re: Electric fan ideas for R129 SL500

i can work out the pwm signal but I reckon we need 3500 CFM to beat the original mechanical fan.

i think the mechanical fan is close to 3000 at the peak maybe 3500

the two front pusher fans will probably contribute less than 1000 cfm

what know from a Ferrari 550 with dual fans

In a few places some list the SPAL VA18-AP70/LL/F-59A (AKA 30102113 - seems SPAL has two different part numbers for their fans) as the replacement 550 fan. That fan per SPAL puts out 3000 CFM and takes approx. 26 amps. It is unsealed and SPAL recommends this fan for racing applications only. I asked if there was potential for the fan to overheat a slow speed/idle and they said it was a possibility (eg they don't know). SPAL does not recommend these fans for use in passenger cars, however, they do say this fan is the closest they have to what is currently in our cars.

you guys are right we will have less flow than a mechanical fan using two 12 inches.

will at least one 16 inch fit? That's just 3000 cfm likely we won't beat the mechanical fan

I am guessing we need 4500 cfm possible 6000 if we delete the front fans.

i need much higher flow 2000 cfm won't work at all

if you anyone has more info please let. I would to get more power but I would more cooling before those wild power upgrades

The Nissens Radiator is a direct replacement size for the OE 500E Radiator. My 500E also has a new later Style m119 Waterpump upgrade and Wahler Thermostat etc.
You are correct my fans are 1150cfm each. I use a Mishimoto controller to kick them in & out depending on temps.http://www.mishimoto.co.uk/mishimoto-fans.html

The fans never ever come on or even come close to coming on when dirving – temp gauge stays pegged at 87c. Then when in traffic they will kick in & out – the fans run maybe 40 – 50% of the time.

IMO the Viscous fan can put out more than 3000cfm when the engine has revs etc – I’d say it can easily move 5000cfm + at full engagement.
For me it was not about beating the mechanical fans (I don’t think that’s possible!) but to eliminate the mechanical fan drag on the motor – with a powerful fan like this that could be anything from 8-15hp.

They key question here is not what CFM Fan you can get – but what will actually fit. You can see how tight these fans are in my 500E – I wanted higher performing ones but anything I looked at would have been too deep. You will find the fan dimensions in the Mishimoto link you posted above (Datasheet for 12 inch fan)

Note that I also will be fitting a resistor to my new front puller fans to kick them in around 100c for extra cooling backup. That way if the car does reach up to 100c on a hot day all 4x fans will kick in.

As for R129 fitment / clearnace I am not sure. Maybe you will have even less space than on a 500E. A 16 fan might work - but again it all depends on the clearances in your car where the motor will sit. I recall looking at 16 fans for my install & IIRC they would not have fitted.

Re: Electric fan ideas for R129 SL500

Do you have anymore details on this? I would like to convert my viscous fan into these twin electric fans.

Does the stock radiator need to be changed out? Who did you get to make the shroud for the fans? Any recommendations would be great!

Cheers

Hi Matin,

I designed the fan shroud and the parts were Plasma Cut then Tig welded by my Brother in a specialist fabricator’s workshop. I don’t think they would do another one as this is not their field of expertise. It was a one off job which my brother got done for me. Member ‘Sayhey’ had made a couple using my plans. Maybe if you PM him he might help with supplying one.

As I said in previous posts Electric Fans are limited in Size due to how little space there is between the Rad & Motor in the 124.036. This limits the performance outputs of fans which will physically fit into that space. Bigger CFM fans are available for sure but they will not fit.

The fans were working AOK - most of the time they were not on at all. One issue that did come to the fore was the Misimoto fan controller was not very reliable. When underhood temps rose it’s kick in temperature also rose which is counter intuitive for it’s function! I tried adjusting several times but it was never 100% happy sometimes not kicking the fans in until over 100c in traffic which bothered me a little.

As fate would have it when I had the car professionally apprised by a MB valuer recently he described to me the importance of originality. So long story short I have reversed a few ‘Mods’ which included the electric fans. I now have a brand new MB Fan Shroud, Beru Viscous coupling and shot blasted / repainted fan blade back in place. The car now runs a permanent 87c on the gauge no matter in traffic or the ambient temp.

I do think it is very hard to get electric fans to match the performance of the factory Viscous fan which is very well designed & pulls MASSIVE amounts of air. It was a fun experiment and I will keep the electric fans & shroud in storage should I wish to re-install. But for now I am happy to run the stock Viscous.

Be prepared to spend £££ on parts (Custom Shroud, 2x Fans + Controller of some sort) to get twin fans to work – and consider if it is worth the effort.

Modern MB brushless electric fans would be awesome for this retrofi - but the controlling / signalling of same would need figured out. Or other threads on 500E board have utilised an off the shelf twin fan + shroud set up but IMO it did not look anywhere near as good as the custom shroud which is designed to look like stock setup.